It is common, in the electronics industry, to use right angled connectors for electrical connection between two printed circuit boards or between a printed circuit board and conducting wires. The right angled connector typically has a large plurality of pin receiving terminals and, at right angles thereto, pins (for example compliant pins) that make electrical contact with a printed circuit board. Post headers on another printed circuit board or a post header connector can thus be plugged into the pin receiving terminals making electrical contact therebetween. The transmission frequency of electrical signals through these connectors is very high and requires not only balanced impedance of the various contacts within the terminal modules to reduce signal lag and reflection but also shielding between rows of terminals to reduce crosstalk.
Impedance matching of terminal contacts has already been discussed in U.S. Pat. Nos. 5,066,236 and 5,496,183. Cost effective and simple designs of right angle connectors have also been discussed in these patents, whereby the modular design makes it easy to produce shorter or longer connectors without redesigning and tooling up for a whole new connector but only producing a new housing part into which a plurality of identical terminal modules are assembled. As shown in '236 patent, shielding members can be interposed between adjacent terminal modules. This requires, however, either an insert to replace the shield or a thicker terminal module to take up the interposed shielding gap if the shielding is not required. The shielding disclosed in the '236 patent has a pin receiving terminal end that is inserted into a housing module cavity and a pin contact end for contacting the printed circuit board. This shield is relatively expensive to manufacture and assemble. The shielded module disclosed in the '183 includes a plate-like shield secured to the module and having a spring arm in the plate section for electrically engaging an intermediate portion of a contact substantially encapsulated in a dielectric material. The shield further includes a pair of spring arms adjacent the board mounting face for engagement with a plated through-hole of a circuit board. This arrangement, however, requires sufficient space between adjacent through-holes of the board to avoid inadvertent short circuits. Furthermore, both the insulated module and the shield must be modified if the ground contact is to be relocated in the connector.